Apparatus for encasing metal pipe in concrete



Jan. 17,1961 G. D. WILLIAMSON ETAL 2,968,081

APPARATUS FOR ENCASING METAL PIPE IN CONCRETE 3 Sheets-Sheet 1 Filed 001;. 24, 1955 ID IVENTORS WILLIAMSON G/LBERT D.

' CHARLES T M NElLL ELMER LEROY TUNSE/V A TTORNEVS Jan. 1961 G; D. WILLIAMSON ETAL 2,968,081

APPARATUS FOR ENCASING METAL PIPE IN CONCRETE Filed 001". 24, 1955 3 Sheets-Sheet 2 mm awz'zvzw m CHARLES r MENEILL ELMER LEROY TUNSEN BYMMM A T TOPNEVS Jan. 17, 1961 e; D. WILLIAMSON ETAL v 2,968,081

APPARATUS FOR ENCASING METAL- PIPE IN CONCRETE Filed Oct. 24, 1955" Y 5 Sheets-Sheet s INVENTORS GILBERT D WILL/AMSCW CHARLES T M NEILL ELMER LEROY TUNSEN A 7' TORNEVS APPARATUS FOR ENCASING. METAL PIPE IN CONCRETE Gilbert D. Williamson and Charles T. McNeiil, Yuiia City, and Elmer L. Tunsen, Modesto, Califl, assignors, by direct and mesne assignments, to Plasti-Con Pipe Co., a corporation of California Filed Oct. 24, 1955, Ser. No. 542,128

2 Claims. (CI. 25-38) The present invention relates to the encasement in concrete of conduits, such as metal pipe, cable, or other type conduits, while said conduits lie directly in the ground.

An object of the present invention is to encase in concrete conduit of various sizes while said conduit is in place in a ditch formed in the ground.

A further object of the invention is to prohibit electrolytic and corrosive action on conduit, such as pipe buried in the ground, by encasing said conduit in concrete.

A still further object of the invention is to form an inexpensive pressure conduit by encasing in concrete in me ground metal tubing that has been reinforced with reinforcing wire.

One form which the invention may assume is exempllfied in the following description and illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a view in side elevation of an apparatus embodying the invention and utilized to practice the improved method.

Fig. 2 is a plan view thereof.

Fig. 3 is a view in longitudinal section taken on the line 33 of Fig. 2, showing the construction and manner of operation of the apparatus in situ.

Fig. 4 is a view in transverse section taken on line 44,of Fig. 1.

Fig. 5 is a view in transverse section taken on line 5-5 of Fig. 1.

Fig. 6 is a view in transverse section through the inner form shell taken on line 66 of Fig. 2.

Fig. 7 is a view in side elevation of an inner form conduit made of relatively thin tubing reinforced with reinforcing wire wrapped tightly around the tube.

It has been found that when two metal pipes of different composition are placed in the ground, they are subject to an electrolytic action which deteriorates the pipes. Also, metal conduit is subject to corrosion by the normal action of water and moisture or other chemicals in the soil. Because of this, in many instances, conduit must be replaced in a comparatively short time. The same elfect occurs on cables that are placed in ground, and usually such cables must be encased in lead which makes such a cable very expensive. There are also numerous cases where telephone cable and other conduits that are buried in shallow trenches in the ground aresevered or damaged by farm and other equipment digging or cutting into the ground.

The present invention makes it possible to encase a conduit, such as a metal pipe, a cable, or a conduit made of other material, in concrete while said conduit is in place in a ditch formed in the ground so that not only is electrolytic or corrosive action stopped, but the said conway by encasing a metal pipe in concrete.

duit is greatly strengthened by the concrete casement and is protected from being damaged or severed by equipment digging or cutting into the ground.

A very satisfactory pressure pipe can be made in th1s The metal pipe may be made of heavy gauge metal, or can be of light metal that is reinforced with a reinforcing wire Wrapping. If it is desired to construct an economical conduit to withstand relative high pressures, the metal tubing can be reinforced with high tensile reinforcing wire wrapped tightly, or pre-stressed around the tubing, and then encased in concrete. 4

The present invention contemplates the formation or digging of a ditch D in the ground, having a bottom portion llil and side walls 11 shaped to conform to part of the conduit that is to be encased in concrete while said conduit is lying in the ditch.

In illustrating the invention, the encasement of a continuous metal pipe will be used by way of example, it being understood that a cable or conduit of other material can be handled in the same way.

As the drawings disclose, it is desirous to completely and continuously encase in concrete a pipe along the length of the ditch cut in the ground in which the pipe lies. Such pipe can be of any shape or configuration and cross-section, it being shown in the drawings, by way of example, as of generally cylindrical form.

A ditch digger (not shown) removes the earth and forms the ditch to the desired depth with the generally semi-circular cross-sectional bottom 10 and side walls .11. After the ditch is formed, then lengths of pipe 12 are laid in the ditch and welded together, said pipe constituting the inner form for constructing the completed conduit. The mechanism A is placed into the ditch around the pipe and along with the configuration of the ditch a form is provided so that when concrete or cementitious material C is poured into the machine A, a continuous casement of concrete or cementitious material is formed around the said pipe to make the completed cement encased conduit. The said mechanism A is moved longitudinally along the ditch D and the concrete is poured into a hopper 13 as needed for distribution around and formation of a cement casement on the pipe in continuous manner within the ditch. The pipe acts as an inner form for the concrete, and the bottom of the ditch conduit. The concrete fed into the upper open end of the hopper l3 flows downwardly through the discharge opening of the hopper 13 and around the said inner form, and the result is a pipe that is completely encased in concrete throughout its length with no breaks, cracks or joints.

Such mechanism A includes the hopper 13 that has, a semi-cylindrical shaped bottom 14 to conform to the configuration of the bottom of the ditch, and includes an upper open end 15 into which the concrete mass C is poured. It is also has a discharge opening 16 at its lower end that overlies the pipe. Included in the lower portion of the hopper is a circular opening 17 which encircles the pipe that is to be encased. Extending rearover the crown of the pipe. Projecting forwardly of the hopper 13 is an arcuate skid 20 conforming generally in shape to the bottom of the ditch, said skid being adapted to slide along the bottom of the ditch. Such sliding action is facilitated by the tapering forward end '21 of said skid.

The arcuate skid 20 merges into parallel side walls 22 of thehopper. .Theserside walls are adapted to slide along the vertical side walls 11 of the ditch. The said skid is reinforced by diagonal reinforcing members 23.

On the upper surface of the skid 20 is a series of rollers.24 that centeraand assistthemachine in travelling longitudinally .of the pipe. These rollers 24 are spaced around the upper face of the skid 20 to conform to the outer shape ofthe pipe that is being encased in concrete. In this way, the said pipe is rolled over the rollers 24.and fedthrough the circular opening 17 of the hopper so that said pipe is properly centered in the ditch with respect to the bottom and sides thereof. Cables 25 are attached to eyes 26 at the forward end of the said skid 20, the opposite end of each of said cables being aflixed to a winch 27. By this means, the concrete that is poured through the hopper is evenly and completely distributed around said pipe.

Concrete C of the proper mix and consistency is poured into the upper open end of the hopper 13 and will naturally gravitate downwardly around the pipe. The rollers 24 keep the pipe properly spaced from the bottom and sides of the ditch, and also properly center the pipe in the circular opening 17 formed in the bottom of said hopper. The cement flows around and completely encases said pipe. A vibrating and tamping mechanism 28, actuated by an engine 29, is attached to the hopper for compacting and tamping the concrete and insuring the proper flow of concrete around the pipe. As soon as concrete is poured into the hopper, the winch 27 is started and pulls the machine forwardly along the ditch at the proper speed. The concrete is fed into the hopper, as needed, so that there is always a sufiicient amount of concrete to completely encase the pipe. The consistency of the concrete mass is such that it will not slump down around the lower edges of the upper portion of the pipe, but will stand to form the concrete crown 19 of cement on the top of said pipe. As the machine A is moved longitudinally in the ditch, the upper outer surface of the concrete crown 19 formed over the pipe is trowelled by the trowelling member 18 to form a smooth crown surface.

Leakage of concrete in a forward direction from the hopper is prevented by a suitable arcuate seal ring 30 in the hopper portion of the device, which slidably engages the periphery of the upper surface of the pipe. Also, the rollers 24 are so positioned that the pipe, as it is fed through the machine, is properly centered with respect to the bottom 10 and sides 11 of the ditch as well as the circular opening 17 of the hopper. In this way, the concrete is evenly distributed around the pipe, and a complete even casement of concrete around the pipe results.

It is preferred to vibrate the concrete to insure its compact disposition in place between the pipe, and the bottom and side walls and trowelling member. Any suitable vibrator and tamping mechanism, as indicated at 28, can be used, so long as all of the concrete being poured around the pipe is vibrated and tamped. The vibrator vibrates the entire hopper and frame as well as the concrete itself to insure the proper flow and denisity of the concrete mass in the ditch and around the pipe. The vibrating effect may be obtained from the gasoline engine 29 that is attached to the hopper and the vibrator may have vibrating or tamping arms disposed within the space between the side walls of the hopper and the ditch to insure a proper vibrating and tamping effect on the concrete being poured around the pipe.

In some installations, as shown in Fig. 7, a very thin metal pipe 31 is employed that has reinforcing wire 32 wrapped therearound. In this way, an inexpensive core of metal reinforced by high tensile reinforcing wire is used as the inner form, so that when the concrete is poured around said pipe, an economical and satisfactory pressure pipe results.

The concrete casing formed by this machine is continuous and, as explained, is poured around the conduit that has been previously laid in the ditch. There are no breaks, cracks, seams, or joints to the casing. When one days operation is completed, the next days operation is carried on where the pouring of the casing was stopped the day before.

In practice, it has been found that the casing formed around a conduit is far superior to other types of casings, for with the use of the present machine, it is unnecessary to handle the conduit being encased once the machine is started. It is also unnecessary to work on or near the top edge of the ditch once it has been formed so that no dirt or foreign matter can come to rest upon the conduit while casing it being poured, thus causing a Weak spot, flaw or break in the concrete casing.

It is apparent that a method and appartus has been provided for encasing in concrete a conduit, while said conduit is in place in a ditch, at a rapid and comparatively economical manner. Such a casement can be formed in extreme lengths without seams or joints. The machine is capable of automatically positioning the conduit in its proper place in a ditch formed in the ground and at the same time conducting concrete into the ditch to evenly pour, spread, and trowel the concrete around the pipe to form a complete casement for the conduit.

While we have shown and described the preferred form of our invention, it is obvious that various changes may be made in its construction by those skilled in the art, without departing from the spirit of the invention as defined in the appended claims.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. Apparatus for producing cementitious conduits in a ditch having bottom and side walls, comprising: an elongated skid member having a leading end, a trailing end and an outer surface of substantially U-shaped crosssection, said skid member adapted for being longitudinally disposed in a ditch with said outer surface engaged with the bottom and side walls thereof; means mounted upon said skid between said leading and trailing ends for supporting a stationary continuous tubular inner form that is adapted to be encased by cementitious material, said support means including transversely and longitudinally spaced roller members that will engage and support said tubular inner form in spaced relation to the bottom and side walls of said ditch; a hopper rigidly mounted at the trailing end of said skid having an upper open end to receive cementitious material and a lower end opening for depositing cementitious material over and about a supported inner form; a rigid screed trowelling means mounted to said hopper and extending rearwardly thereof; and a sealing member fixed relative to said skid member extending downward from the leading edge of said lower hopper opening and engaging the peripheral surface of a supported tubular inner form to prevent forward leakage of the cementitious material; whereby a stationary tubular form member extending longitudinally of said ditch and supported upon the roller guide members of said skid can be expeditiously encased with cementitious material by moving said skid forwardly in said ditch, cementitious material being fed into said upper hopper opening and deposited over said tubular form member; said roller guide members allowing said skid to be moved longitudinally of said ditch and from between said inner form and said ditch and said sealing member preventing forward leakage of the cementitious material onto said skid.

2. The apparatus of claim 1 including means for continuously advancing said skid longitudinally of said ditch at a uniform rate, and a vibrating means affixed to said hopper for imparting vibration thereto, causing said cementitious material to flow rapidly over said stationary tubular inner form.

(References onfollowing page) References Cited in the file of this patent UNITED STATES PATENTS Detrick Nov. 6, 1883 Howson Jan. 8, 1884 5 Boyle June 25, 1907 6 Rees Nov. 7, 1911 Wilson Nov. 15, 1932 Lines Apr. 1, 1941 Breedlove Sept. 16, 1941 Jerner Nov. 6, 1951 Tunsen Jan. 24, 1956 

